const arr=[
    [1,2,3,4,5],
    [1,2,3,4,5],
    [1,2,3,4,5],
    [1,2,3,4,5],
    [1,2,3,4,5]
]
//长方阵列排列的复数或实数 矩阵=>二维数组 构建数组高级用法基础

